4 research outputs found
A new paediatric formulation of valaciclovir : development and bioequivalence assessment
Peer reviewedPostprin
First principles investigation of exchange interactions in quasi-one-dimensional antiferromagnet CaV2O4
The effect of orbital degrees of freedom on the exchange interactions in the
spin-1 quasi-one-dimensional antiferromagnet CaV2O4 is systematically studied.
For this purpose a realistic low-energy model with the parameters derived from
the first-principles calculations is constructed. The exchange interactions are
calculated using both the theory of infinitesimal spin rotations near the
mean-field ground state and the superexchange model, which provide a consistent
description. The obtained behaviour of exchange interactions substantially
differs from the previously proposed phenomenological picture based on the
magnetic measurements and structural considerations, namely: (i) Despite
quasi-one-dimensional character of the crystal structure, consisting of the
zigzag chains of edge-sharing VO6 octahedra, the electronic structure is
essentially three-dimensional, that leads to finite interactions between the
chains; (ii) The exchange interactions along the legs of the chains appear to
dominate; and (iii) There is a substantial difference of exchange interactions
in two crystallographically inequivalent chains. The combination of these three
factors successfully reproduces the behaviour of experimental magnetic
susceptibility.Comment: 15 pages, 6 figures, supplementary materia
The role of formulation on the pharmacokinetics of antiretroviral drugs
INTRODUCTION: A multitude of antiretroviral drug formulations are now available for HIV-infected adults and children. These formulations include individual and co-formulated drugs, many of which are also supplied in generic versions. Many antiretroviral drugs have a low aqueous solubility and poor bioavailability. Drug formulation can significantly affect bioavailability, and given the increasing number of new formulations and drug combinations, it is important to be aware that formulation can influence the pharmacokinetics of antiretroviral drugs. AREAS COVERED: This review provides an overview of studies assessing the pharmacokinetics of different antiretroviral drug formulations in adults and children, including fixed-dose combinations. For some antiretroviral drugs, differences in pharmacokinetics have been described, with largest differences in exposure when a liquid formulation is compared to a tablet or capsule formulation. Biopharmaceutical properties of antiretroviral drugs relevant to bioavailability are discussed. EXPERT OPINION: Antiretroviral drug formulations and their excipients can significantly impact drug exposure. However, this is not yet fully recognized. It is important to realize that children use different formulations than adults. Effort should be made to ensure that adequate drug exposures are achieved to treat HIV-infected children. In addition, manipulation of drug formulations may lead to differences in pharmacokinetics